Non-traumatic Causes of Brown-Sequard Syndrome: A Case Series and Clinical Update with Systematic Review.

Background: Brown-Sequard syndrome (BSS) is a rare neurological condition resulting from a hemisection injury to or unilateral compression on the spinal cord. The most common causes of BSS that are amenable to be treated surgically can be divided into traumatic and non-traumatic injuries. Traumatic injuries are often reported as the main cause of BSS. However, non-traumatic injuries of the spinal cord have been shown to be more prominent in recent years. Objective: To classify and update surgically treatable causes of BSS. Methods: Retrospective data of 17 patients operated for BSS between 2008 and 2020 were included. The long-term outcomes of these patients were evaluated. In addition, a comprehensive search in PubMed, Scopus, and CINAHL was conducted for retrieval of all relevant studies. Results: Magnetic resonance image (MRI) of our patients revealed cervical disc herniation (CDH), cervical spondylosis, spinal canal stenosis, epidural hematoma, and ossification of the posterior longitudinal ligament. The postoperative outcomes of our cases ranged from partial to complete recovery. While the patients with acute epidural hemorrhage achieved complete recovery after surgery, neurological deficits in the other patients, especially those with severe cervical spinal canal stenosis, persisted despite adequate surgical decompression. The systematic literature review revealed that CDH is the most common non-traumatic surgically treatable cause of BSS followed by spinal cord herniation and spinal epidural hematoma. Conclusions: Non-traumatic injuries of the spinal cord accompanied by narrowed cervical spinal canal pathologies have been shown to be prominent surgically treatable causes of BSS. Contrary to the definition made 100 years ago, it has been observed that it can occur spontaneously due to underlying pathologies rather than major traumatic injuries.